manuals: add initial sphinx-lint support

Makes it possible to catch errors not reported by sphinx,
such as idle spaces. After customization, this should be used
to enforce our syntax conventions, such as two spaces after a "-"
character to introduce a list item.

Just run "make sphinx-lint".

(From yocto-docs rev: 9e1aeeddca06cb7d65631010ba0eebdcd8ecf9ee)

Signed-off-by: Michael Opdenacker <michael.opdenacker@bootlin.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

documentation/Makefile

@@ -53,6 +53,9 @@ stylecheck:
 	vale sync
 	vale $(VALEOPTS) $(VALEDOCS)
 
+sphinx-lint:
+	sphinx-lint $(SOURCEDIR)
+
 epub: $(PNGs)
 	$(SOURCEDIR)/set_versions.py
 	@$(SPHINXBUILD) -M $@ "$(SOURCEDIR)" "$(BUILDDIR)" $(SPHINXOPTS) $(O)

documentation/README

@@ -165,6 +165,20 @@ To run Vale:
 
  $ make stylecheck
 
+Link checking the Yocto Project documentation
+=============================================
+
+To fix errors which are not reported by Sphinx itself,
+the project uses sphinx-lint (https://github.com/sphinx-contrib/sphinx-lint).
+
+To install sphinx-lint:
+
+ $ pip install sphinx-lint
+
+To run sphinx-lint:
+
+ $ make sphinx-lint
+
 Sphinx theme and CSS customization
 ==================================